Researchers have used new micro-computed tomography (micro-CT) scanning techniques to imagea bumblebee’s (Bombus terrestris) dinky brain in unprecedented detail.
The pictures and findings, published on Wednesday in a study in Scientific Reports, will allow researchers from Imperial College London to learn more about the bee’s cerebral processing power and help them get to the bottom of why its brain malfunctions in certain situations.
“What’s novel about this research is how we’re able to explore such a miniature brain,” said Richard Gill, paper co-author and a lecturer in the division of ecology and evolution at Imperial College London. “We can keep the brain in its normal stereo geometry, and we can keep going back to the images and samples as much as we like. It’s a non-destructive method as we don’t have to take the bee’s brain apart.”
Researchers used CT scanning to image a bee brain. Image: Dylan Smith/Imperial College London
The paper explains that CT scanning—which uses X-rays to provide hundreds of image slices of an object—has long been used to explore how the “volume, shape, and density of particular human brain regions.” However, there are a dearth of studies like this when it comes to the bee’s pea-sized brain.
Why? Up until now, researchers haven’t been able to deal effectively with some of the logistical issues presented by a bee brain; the teeny composite structures are pretty hard to manipulate, prepare, and observe in high-res.
Scanning avoids physically taking the bee's brain apart. Image: Dylan Smith/Imperial College London
Previous techniques saw researchers physically removing and slicing up insect brains—causing damage to the tiny structures during the process, and scuppering the chance of accurate measurements of their shape and size. The new micro-CT techniques have jumped this hurdle, allowing researchers to recreate 3D reconstructions of 19 bee brains using an open source visual analysis software called SPIERS. This allows them both to visualize the whole brain and look at the individual components making up its structure.
Why bother imaging a brain that’s infinitely less complex than a vertebrate’s? According to the researchers, foraging insects like bees have to learn to deal with a complex array of sensory, landscape, and chemical cues while they search for pollen. Understanding how the bee deals with these challenges will help investigate how a tiny and much more simple brain generates complex multitasking behavior, as well how the bee’s navigating behavior evolved.
Researchers also want to understand how trauma affects bee brains. Image: Dylan Smith/Imperial College London
“Bees are known to perform very complex tasks considering the size of their brains and their simplicity compared to high-level organisms,” said Gill. “If we can focus on simple tissues and find the small changes that can have profound effects on behavior, it can give us a basis to start understanding how very small changes to that brain can do that.”
Next up, the researchers aim to use the micro-CT scanning technology to understand how trauma affects the bee’s brains, and subsequently their ability to forage for food.